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[SCSI] libiscsi: Restructure iscsi_tcp r2t response logic 

Restructure the iscsi_tcp_r2t_rsp routine in order to avoid allocating
r2t from r2tpool.queue and returning it back in case the parameters
rhdr->data_length and or rhdr->data_offset prohibit the requing.

Since the values of these parameters are known prior to the allocation,
we can pre-check and thus avoid futile allocations.

[jejb: checkpatch fixes]
Signed-off-by: Shlomo Pongratz <shlomop@mellanox.com>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
This commit is contained in:
Shlomo Pongratz 2014-02-07 00:41:37 -06:00 committed by James Bottomley
parent ac0245ff80
commit 5d0fddd0a7
1 changed files with 26 additions and 25 deletions
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51
drivers/scsi/libiscsi_tcp.c
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@ -529,6 +529,8 @@ static int iscsi_tcp_r2t_rsp(struct iscsi_conn *conn, struct iscsi_task *task)
struct iscsi_r2t_rsp *rhdr = (struct iscsi_r2t_rsp *)tcp_conn->in.hdr;
struct iscsi_r2t_info *r2t;
int r2tsn = be32_to_cpu(rhdr->r2tsn);
u32 data_length;
u32 data_offset;
int rc;
if (tcp_conn->in.datalen) {
@ -554,7 +556,28 @@ static int iscsi_tcp_r2t_rsp(struct iscsi_conn *conn, struct iscsi_task *task)
return 0;
}
rc = kfifo_out(&tcp_task->r2tpool.queue, (void*)&r2t, sizeof(void*));
data_length = be32_to_cpu(rhdr->data_length);
if (data_length == 0) {
iscsi_conn_printk(KERN_ERR, conn,
"invalid R2T with zero data len\n");
return ISCSI_ERR_DATALEN;
}
if (data_length > session->max_burst)
ISCSI_DBG_TCP(conn, "invalid R2T with data len %u and max "
"burst %u. Attempting to execute request.\n",
data_length, session->max_burst);
data_offset = be32_to_cpu(rhdr->data_offset);
if (data_offset + data_length > scsi_out(task->sc)->length) {
iscsi_conn_printk(KERN_ERR, conn,
"invalid R2T with data len %u at offset %u "
"and total length %d\n", data_length,
data_offset, scsi_out(task->sc)->length);
return ISCSI_ERR_DATALEN;
}
rc = kfifo_out(&tcp_task->r2tpool.queue, (void *)&r2t, sizeof(void *));
if (!rc) {
iscsi_conn_printk(KERN_ERR, conn, "Could not allocate R2T. "
"Target has sent more R2Ts than it "
@ -563,30 +586,8 @@ static int iscsi_tcp_r2t_rsp(struct iscsi_conn *conn, struct iscsi_task *task)
}
r2t->exp_statsn = rhdr->statsn;
r2t->data_length = be32_to_cpu(rhdr->data_length);
if (r2t->data_length == 0) {
iscsi_conn_printk(KERN_ERR, conn,
"invalid R2T with zero data len\n");
kfifo_in(&tcp_task->r2tpool.queue, (void*)&r2t,
sizeof(void*));
return ISCSI_ERR_DATALEN;
}
if (r2t->data_length > session->max_burst)
ISCSI_DBG_TCP(conn, "invalid R2T with data len %u and max "
"burst %u. Attempting to execute request.\n",
r2t->data_length, session->max_burst);
r2t->data_offset = be32_to_cpu(rhdr->data_offset);
if (r2t->data_offset + r2t->data_length > scsi_out(task->sc)->length) {
iscsi_conn_printk(KERN_ERR, conn,
"invalid R2T with data len %u at offset %u "
"and total length %d\n", r2t->data_length,
r2t->data_offset, scsi_out(task->sc)->length);
kfifo_in(&tcp_task->r2tpool.queue, (void*)&r2t,
sizeof(void*));
return ISCSI_ERR_DATALEN;
}
r2t->data_length = data_length;
r2t->data_offset = data_offset;
r2t->ttt = rhdr->ttt; /* no flip */
r2t->datasn = 0;